The invention relates to a clamping device to facilitate affixation of a prosthetic patella component to the natural patella during knee arthroplasty procedures.
Knee arthroplasty procedures require the resection of the natural articulation surface of the patella and replacement thereof with a prosthetic patella component. Subsequently, through known procedures, the resected surface of the patella is reamed to form a cavity that can accept the patella prosthesis. The cavity is filled with bone cement and the patella prosthesis is inserted within the cavity. Thereafter, the natural patella and the prosthesis must be held together firmly until the cement cures. Typically a special clamping device is used to hold and apply pressure to these components.
A number of clamping devices are known to exist. For example, U.S. Pat. Nos. 5,284,482; 5,129,908; and 4,706,660 all disclose various patella clamping devices. These patents describe clamp devices that require two hand operation: one hand closes the clamp while the other uses a thumb screw or a similar device to lock the clamp in the closed position. The design of the disclosed clamps is such that the closing motion of the clamp is non-linear.
Patella clamping devices generally include two jaw elements that close together to engage and hold firmly the prosthetic patella component and the natural patella. It is desirable for the jaws to close together in a consistent manner with a linear application of force so that the components are not drawn out of alignment while the load is applied. Once the jaws are closed to apply the load to the two components, the jaws must be held together firmly with a constant application of pressure. To accomplish this, it is often necessary to lock the jaws in place.
Many patella clamps have locking devices to maintain the jaws of the clamp in the closed, load applying position. Known clamp designs, such as those described in the references noted above, usually require the surgeon to maintain pressure on the clamping jaws with one hand while using the other hand to actuate the locking mechanism. The necessity for the surgeon to use two hands during the locking procedure can be inconvenient. It would thus be advantageous to provide a clamping device that enables the linear application of load and which enables locking of the device using only one hand.
Many patella clamps also do not permit the clamping members to close with a vertical or linear application of load. A non-linear closing motion of a clamp could result in the application of forces which cause misalignment of the patella components while the clamping load is applied.
Accordingly, an object of the invention is to provide a patella clamping device that enables the linear application of clamping load and the ability to lock the clamping jaws in place using only one hand. It is also an object of the invention to provide a patella clamp that can be used with greater ease and accuracy. Further objects will be apparent to those having ordinary skill in the art on reading the disclosure that follows.